Retractable soot blower



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Dec. 7, 1954 LE ROY 5. DE MART 2,696,016

RETRACTABLE SOOT BLOWER Filed April 11, 1950 8 Sheets-Sheet 4 Dec. 7,1954 LE ROY 5. DE MART 2,696,016

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RETRACTABLE SOOT BLOWER Filed April 11, 1950 8 Sheets-Sheet '7 INVENTOR.

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' RETRACTABLE SOOT BLOWER Filed April 11. 1950 8 Sheets-Sheet 8 uINVENTOR.

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United States Patent RETRACTABLE soor BLOWER Le Roy S. De Mart, Detroit,MiClL, assignor to Diamond Power Specialty Corporation, a corporation ofOhio Application April 11, 195th Serial No. 155,304

17 Claims. (Cl. -317) This invention relates to cleaning devices of theclass employed in cleaning the heat exchanging surfaces of boilers andthe like, and which are commonly known in the trade as soot blowers.

The primary object of the present invention is to provide an improvedrotary retracting soot blower which employs only a single extensible andretractable blower tube, having a blower nozzle at its end, and which iscapable of relatively long travel, being operable through the agency ofprojecting and retracting mechanism of a unique, simple and reliablecharacter, and which achieves advantages not heretofore obtainable in asingle structure of this class.

Among important advantages of my invention may be mentioned the factthat my improved soot blower is operable by extremely compact drivingmechanism which may be located close to the wall of the furnace orboiler, while the retractable and extensible portions of the blowerwhich project rearwardly from such driving mechanism are fully enclosed,due to the inherent construction of the blower, so that if desired, suchprojecting portions may extend outwardly from the building containingthe boiler and into the open air, a great saving being thereby effectedin that the building need not be large enough to enclose all portions ofsuch soot blower assemblies, even though they be of the long-retractingtype. Soot blowers constructed in accordance with my present inventionincorporate a stationary threaded driving element which also serves as asupport for the blower tube, and a feed conduit through which theblowing fluid is supplied to the blower tube and'nozzle, novel meansbeing incorporated for rotating the blower tube and for simultaneouslyrotating a traveling driving nut secured to the blower tube to projectand retract the blower tube.

Another object is to provide such a traveling blower wherein all of theparts which are subjected to high temperatures are of smooth, circularconcentric cross section, with no angular contours such as keyways orsplines in the areas exposed to the products of combustion. Due to thesmooth contour of such parts of my improved blower, warpage is reducedto a minimum, fouling is minimized, and the improper functioning whichis sometimes caused by the tendency of foreign matter to accumulate inkey- Ways and the like is obviated.

it is an important object of this invention also to provide improveddriving means for a smooth surfaced telescopic or sliding tube such as ablower tube.

Still another object is to provide an improved soot blower of theindicated character, wherein all of the driving components, and most ofthe controlling elements which activate and regulate the action of theblower are located close to the boiler or furnace wall, in a compactassembly which is conveniently accessible for servicing and adjustment.

A further object is to provide an improved control system for blowers ofthe indicated class arranged in such manner that although eachindividual blower is sequentially operable under the supervisory controlof a central automatic control station remote from the blower, asubordinate control system located appurtenant to the blower itselftakes over important aspects of the controlling function during eachoperating cycle of the blower, and prevents the operation of the blowerfrom being interrupted priorto complete retraction of the blower, evenif a failure should occur at the central automatic control stationduring the operation of the blower.

Another object of the invention is to provide improved sealing means forpreventing unwanted leakage, which sealing means is readily accessiblefor servicing.

Still another object is to provide improved subordinate controlmechanism at the blower station which will immediately cause retractionof the blower in event the supply of blowing medium fails duringoperation of the blower.

Other objects and advantages of the invention will become apparent uponconsideration of the present disclosure in its entirety.

In the drawings:

Figure l is a side elevational view of the forward portion of aretractable soot blower constructed in accordance with the presentinvention, partly broken away and with the control panel cover removed;

Fig. 2 is a similar view, partly broken away, of the rear portion of theblower;

Fig. 3 is a longitudinal sectional view upon a larger scale showing theprincipal components of the driving mechanism;

Fig. 4 is a longitudinal sectional view of the blower tube and blowingfluid supply means;

Fig. 5 is a cross-sectional view taken substantially on the line 5-5 ofFig. 3, and looking in the direction of the arrows;

Fig. 6 is a sectional detail partly broken away, taken substantially onthe line 6-6 of Fig. 5, and looking in the direction of the arrows;

Fig. 7 is a cross-sectional view taken substantially on the line 77 ofFig. 1 and looking in the direction of the arrows, but with the controlbox removed;

Fig. 8 is a fragmentary elevational detailed view, taken substantiallyas indicated by the line and arrows 8-8 of Fig. 7;

Fig. 9 is a sectional detail taken substantially on line 99 of Fig. 3and looking in the direction of the arrows, on a larger scale;

Fig. 10 is a cross-sectional view taken substantially on the line 101tlof Fig. 1, and looking in the direction of the arrows;

Fig. 11 is a rear elevational view of the control panel, takensubstantially on line 1111 of Fig. 10, and looking in the direction ofthe arrows;

Figs. l2, l3, l4, l5 and 16 are sectional views taken substantially onthe lines 12-42, 1313, 1414, 15-15, and 1616, respectively, of Fig. 2,and looking in the direction of the arrows;

Fig. 17 is a sectional elevational view, partly broken away, of a mainblower control valve;

Fig. 18 is a sectional detail of a three-way valve forming a part of thecontrol system;

Fig. 19 is a schematic diagram;

Fig. 20 is a longitudinal sectional elevational view showing a somewhatmodified driving construction;

Fig. 21 is a cross-sectional view taken substantially on the line 2121of Fig. 20, and looking in the direction of the arrows;

Fig. 22 is a crosssectional view similar to Fig. 20, showing a furthermodification; and

Fig. 23 is a longitudinal sectional view of the principal mechanicalcomponents of a blower of somewhat modified construction.

Referring now to the drawings, my improved soot blower constructionincludes a slidable blower tube as 20, which is projectable through anopening as 22 in a boiler-wall or the like, the wall beingfragmentarily, diagrammatically indicated at 24. The blower tube is ofsmooth cylindrical form and carries a blower nozzle as 25, through whichsteam, air, or a combination of these, or other desired cleaning fluid,may be projected against boiler tubes or other heat exchanging surfacesto be cleaned. When retracted, the blower tube 20 lies entirely outsidethe high temperature zones within the boiler or furnace. A relativelyheavy main casing 27 surrounds the slidable blower tube outside thesupporting wall 24 and may be directly attached to and carried by thewall, through the agency of a wall box as 29, to which the substantiallycircular front wall 30 of the casing is bolted.

Rotatably mounted in the casing 27, as in front and rear "ball bearings'32, 33, and coaxial'ly surrounding the blower tube 20, is a driving andsupporting sleeve 35. At its forward end, the sleeve 35 is substantiallysealed-with respect to the front opening inthe wall of the casing as bya sealing ring '36. The blower tube 20 is fitted to slide easilywithinthe sleeve 35. A worm wheel'37 is keyed to the 'sleeve 315 within thecasingand drivable by a worm 39, which is in turn rotatable by asuitable driving motor such as the air motor 40. Atits rear end, thesleeve is also sealed externally with respect to the casing as by meansof the sealing rings 42, 43, which coact with a flange 46 on sleeve 35to divide the casing-into two compartments. One compartment, designated44, contains the worm and worm wheel 39, 37, and the other, designated45, serves to house arotatable cage '47 secured as by screws -48 to therearface of -flange 46 of sleeve "35. "Cage-47 surrounds and isrotatable concentrically with the'blower tube 20.

The cage 47 carries threerollers 50, 52, 54, the first two of whichconstitute driving rollers, white roller-54 serves as a reactionelement. Each of the "rollers is positioned approximatelytangentiallyand journaled on a supporting shaft as '55, 56, 57, perpendicular to theblower tube, the rollers being formed of hardened material, engaging thesurface of the blower tube and rotatable therealong during projectionand retraction of the tube.

Each of the rollers-is provided with peripheral serrations, as indicatedat 58, to increase the unit pressure between'the rollers and the'blowertube and reduce any tendency of the rollers toslip when they areperforming their function of driving the tube rotatably. Each of' therollers is carried bya'gimbal-type mounting consisting of afloating'ring as 60, supporting the roller shaft- (55 in Fig. 6) andtrunnioned as by means of trunnion studs 62, 64, for rockingmovementabout an axis perpendicu lar to'the axis of theroller shaft. Asbest shown in Fig. 6, the gimbal rings may be of generally rectangularform,'although this is ofcourse subjectto variation,-an to-reduce wear,a bearing sleeve'65 is interposed between each roller and its shaft, andthrust bearing washers as 66,:67 are arranged upon the'shaft at each endof the roller, between the roller and the sides of the gimbal ring.

The gimbal rings of the driving rollers 50, 52 are urged in oppositeangular directions about the axes of their gimbal studs 62, 64, by meansof a tension spring 70 secured as by screws 72 to the adjacent ends ofsuch gimbal rings andreacting in opposite angular directions thereupon.roller52 clockwise, as the parts are'viewed in Fig.5, and tends to rockthe gimbal ring of the roller 50 counterclockwise. The gimbal ring ofthe reaction roller 54 floats freely upon its supporting studs62,6'4,'no spring means beingprovided to urge'it in either direction.

To the rear of the compartment '45, the casing 27 is necked inwardly andprovided-with a reduced tubular flangeportion 75,'in which is tightlyfitted a casing tube 77 extending rearwardly therefrom to serve as anenclosure for the slidable blower tube and other parts. At its-rearextremity, the casing tube 77 supports "an externally threaded tube 79which projects forwardly withinthe blower tube to a'position near theplane of the boiler wall 24, as shown in 'Fig. 3, although the length ofthe tube 79, like the length of the blower tube itself. is subject tovariation, as will be appreciated. The tube 79 is provided throughoutthevmajor proportion of its length with external screw threads, asindicated at '80, and near its forward extremity carries a packingassembly, generally designated 82 and indicated as of theherringbone-type. The packing assembly issupported by a sleeve 83threaded upon the tube 79 and locked in position with respect thereto bysetscrews 84. The sleeve is sea ed with respect to the guide tubebv'plastic'packing 85 injected throughaplugged opening86 into an annularchamber 87 formed in an enlargedrear flange portion 88 of the sleeve-83.Flange -88 forms a retainer-for the rear end of the packing and alsoforms an abutment to limit theextent .of projection of the blower tube.Setscrews 84 retain upon the front peripheral portion of sleeve 83 afront retainer ring 89 which also serves, with the front end of thesieve, to limit theretracting travel of the blower tube. It will benoted thatthe blower tube '20 is somewhat shorter than the guide tube79. In order to gain access to the packing assembly 82 for Spring'7tltends to'rock the gimbal ring of elements.

the'top section 29 ofthe'wall"box,remove'the blower nozzle 25, and backthe blower tube off the packing assembly. The packing can thus be easilyserviced without disturbing or disassembling any of the major componentsof the blower actuating or controlling mechanism.

At its rear end. the screw tube 79 is rigidly held by means of aclamping ring '90,'having a neck 'portion 91 which projects into and issnugly fitted with respect to the rear end 'of the casing tube'77, towhich it is attached by means of setscrews 92 projected throughapertures (undesignated) in the wall of the casing tube.

A blowing-fluid supply pipe 93 is so coupled with respect to the rearend of the screw tube 79 as to permit feeding of blowing fluid into therear end of the screw tube, and it will be noted that the forward end ofthe screw tube is open to the interior of the blower tube 20, so-thatthe screw tube'serves as means for delivering the blowing fluid to theblower tube. The means .for coupling the supply pipe is shown as-comprising a-coupling ring 94 with which the supply pipe is threadedlyengaged, the coupling'ring beingsecured as'by means of screws 95 to theterminal ring90 carried 'by'the rear'endof the casing tube 77. A sealinggasket'as 96 may be interposed between the rings 90, '94. It will beobserved that the external threads 'stl of the screw tube extend intothe conformably internally threaded ring portions'90, '91 to provideadditional holding means between these elernents.

A seal is preferably provided between the casing tube 77 and screw tube79, and may comprise injected'plastictype'sealing material, designated97, retained under compression in an annular space between the inner endof the neck'91 and a spaced backing retainer ring 99 threaded onto theexternal threaded surface of the screw tube 79 and snugly fitting theinterior of the casing tube '77, and held inspaced relation with respectto the neck 91 as by meanso'f locating'p'ins 100 extending through theretainer ring 99 and into the forward end ofthe neck 91. :Theplastic"sealing material may be injected and replenished through a normallyclosed orifice sealed by a removable screw :plug 102.

A tubulardriving nut is fast upon the rear end of the blower tube 20andinternally threadedly interen- .gaged with the external threads '80of the screw tube 79.

It will be noted upon reference to Figs. 5 and 6 that the (common) axisof the gimbalstuds'62, 64 is spaced outwardly from the axis of theblower tube 20 a greater radial distance than is the rolling axis oftherollerSt) (the latter axis being defined by the 'axis of spindle 55).This is also true in the case of each of the other two 'gimbal-mountedrollers 52, 54. When the cage is rotatably driventhrough the drivingmeans, previously described, comprising the worm 39, worm wheel 37 andsleeve 35,'the rollers are moved in a'planetary path and the teeth'oftherollers ten'dto rotate the blower tube about-its axis. Referring to Fig.5, assuming'that the drive is such as to turn the cage 47 in a clockwisedirection, the drive is transmitted to the 'gimbal ring 60 of'the roller'52 through to the gimbal studs 62, 64. Due to the tendency of theroller to'drag upon the blower tube, the gimbal ring is urged'clockwiseabout the axis of the gimbal studs 62, 64. This rocking influence uponthe gimbal ring is assisted by the spring 70. The roller 52, like'theother rollers 50. 54 of the assembly, is of hourglass-shape. Theexternal hourglass curvature of the rollers is on a radius somewhatexceeding the radius of the blower tube,'so that such rocking of thegimbal about the axis of the gimbal studs tends to force portions of theroller 52 of increasing radius into tighter peripheral engagement withthe blower tube, and the'serrated surface of the roller is therebydriven into tight wedging engagement with the blower tube. Since theblower tube possesses a certain amount of inherent lateral flexibility,the wedging action of the driving roller 50, urging the tube inadirection radially inwardly from the roller 52, drives spaced portionsof the tube 20 tightly against the rollers 50, 54, both of which thenserve as reaction The blower tube is thereby tightly located and heldupon three sides through the interaction of the rollers in the mannerdescribed, and the rollers, in response to the rotation of the cage,exert a tangential drag upon the blower tube in the direction ofrotation. The grip of the rollers is so effective as'to turn the blowertube at'the full speed of thecage, and thedrivings nut portion 105,(Fig. 4) being thereby turned=upon the threaded portion 80' of the screwtube 79,. drives. the blower'tubelongitudinally With respect to thescrewtube in: response to such rotation.

to extend it: farther into the interior'of' the boiler.

tion will cause the principal wedging'eif'ect tobe exerted through: theroller. 50, which is preliminarily biased in a counterclockwisedirection, as:viewed in Fig; 5, about the axis of its girnbal studs bythe counterclockwise-acting end ofspring 70. The rollers 52', 54 thenserve as the reaction elementsand the blower tube is reversely rotatedand resultantly axially reversely driven to rotate it-' in the oppositedirection and retract it to the protected withdrawnposition in: which itis shown in Fig. 3.

The driving air mtor40' is mounted upon a flat top surface portion 113ofthe casing 27 in a position to-the rear of the plane of the wormandthewo'rm wheel 39,

37; onlya fragment ofthe air. motor being illustrated in- Fig. 7. Sincethe details of'construction of the air motor parent that the rate atwhich the blower tube is driven can be changed by substituting gears ofdifferent proportions.

The compartment 44 containing the Worm and Worm wheel is substantiallysealed by the sealing rings 36', 42, at its opposite ends and may becharged with lubricant. Any pressure developed between the tubes 20, 79behind the packing 82 is communicated to the space 124 betweenthe'casing tube 77 and the blower tube 20 through orifices 122, formedin the wall of the blower-tube 29 near its rear end. The space 124communicates with the compartment 45 within the casing 2'7, as'best'shown in Fig. 3, and as also shown in that view, the internal diameterof the sleeve 35 is enlarged throughout a portion of its length bycountcrboring the same from its rear end, as indicated at 126, forapproximately two-thirds of its length. The counterbored enlargement1.26 communicates with the interior of' the wall box 29 through ahelical groove 69, which is also formedin the interior wall of thesleeve 35, and which extends forwardly to provide fluid connectionbetween the enlargement 126' and the interior of the wall box, and thuswith the space within the furnace. Although axial grooving could" beemployed in place of the helical groove 69, I prefer the helical grooveformation for the reason that there is less tendency toclogging,inasmuch as the realtive rotation of' the parts and the flow through thehelical passage 69'- tend to carry any fouling material out of suchhelical passage. I preferably also deliver the exhaust of the air motor40 to the chamber 45within the casing 27, so

that the discharged air from the motor also passes throughv thecounterbored' portion 126 and passage 69 to the interior of the boiler,thereby assisting in maintaining positive pressure within the boiler andalso in preventing clogging of the passages 69, 126, while the motorexhaust'may be connected at any point to the portion of the casing 27which defines chamber 45 or to the casing tube 77, such connection isindicated as effected by means of: a conduit 117 which extendsrearwardly along the sideof the casing tube 77' to the housing 171 forthe rear actuating lug 160.

As shown in Fig. 2, the conduit 117 may besupported by the same bracketelements 316 which carry the rods 152, 315. The actuating lug housing171 is provided with a port 395 to which the conduit 117 is coupledtoprovide communication between such conduit and the interior of thehousing 171. Conduit 117 communicates interiorly with the casing tube 77through the slot 162 (Fig. 15).

Thus the exhaust from the motor passesthroughout theentire length of thecasing tube and is discharged into the furnace through the counterboredchamber 126 andhelical slot 69, inthe manner previously described. Thisarrangement: is such that the motor exhaust is in con- If: right-handthreads are provided upon the screw tube-and: driving nut 105; suchrotation of the cage and rollers in a clockwise direction, as'viewediinFig. will project the blower: tube outwardly. Con-- versely, rotationofthe cage in a counterclockwise:direc-- motor air serves to lubricate theworking parts of the blower as well as-the motor and the motor controlvalving mechanism.

It Will be observed-that in the preferred construction illustrated inFigs. 1-19, the portion of the fixed. screw.

tube-79, which carries the packing assembly 82', projects.

beyond the front wall plate 30 of the casing 27. In event it becomesnecessary to service the front packing 82', therefore, his onlynecessary to pull the blower tube back clear of such packing, Withthenozzle element 25 removed. This will be-seen to' expose the packing forconvenient servicing. As shown in Fig; 1, the wall box is formed inseparable sections,.which facilitates such access.

Although the means for automatically controlling the projection andretraction of the blower is subject to variation, my preferredarrangement, shown schematically in Fig. 19, employs a reversing valveassembly corresponding to the disclosure of my copending applicationSerial No. 60,435,- filed November 17, 1948, now patent No. 2,623,534.The reversing valve assembly is generally designated 121 (Fig. l) and ismountedon a control'panel 123: secured as by means of screws 12?; to apad 125 formed on the side of the collar'fiange 75 of casing 27.The-details of construction of the control valve 121 form no part of mypresent invention and may be derived from my previously mentionedcopending application.

The valving components actuatable by such stems are incorporated in acontrolling system'which is so arranged that when the. stem 127 isprojected outwardly with respect'to the valve body 121, as by thehelical compression, spring 130, the valving components provideconnections between the air supply and exhaust conduits 133, 117 and theair motor 40, of' such character that motor power air is delivered tothe motor in a-direction to'driver it forwardly, that is, in, adirection to project theblower unit.. When the stern 127 is pressedinwardly against the resistance of the spring 130, while stem 129 is inthe projected position (under the influence of the spring 132) the airconnections to and from the motor are reversed, to cau'se'themotor'toreverse its direction ofrotationand'retract the blower. During suchreverse rotation and retracting movement of the blower, the stem 127 isheld depressedby the biasing effect of air pressure uponavalvecomponent372 carried by such-stem. Upon completion of theretracting movement ofthe blower, the stem 129-is depressed, and in the system disclosed in myaforementioned copending application such actuation of stem 129 acts tocause the supply of motivating air l to the blower motor to be cut off,so that the blower improved further upon these control features incertain respects which will presently'be discussed.

The stems 127, 129 of the motor control valve are mechanicallyactuatableby the blower tube as it completes its forward and reversetravel. The stems are actuatabl'e by a lever 14h rockably mounted on astud 135 carried by the-panel123; A blade-like arm 1371s independentlypivoted on stud 1 35 and extends down- Wardlyin a position overlying thelower arm 138 of the lever; Arm 13'2" extends across the end of the stem127. AnupWardly extending arm 139 of lever 14%? overlies the stem 1 29".Adjustable abutment screws 141, 143' are carried by the arms 138, 139,respectively. Abutment screw 141 is engageable' with the lower extremityof arm 137 to limit independent relative movement of the arms 137, 138inone direction, the arrangement being such that arm 137' can move awayfrom the abutment screw 141 to the left or clockwise, as viewed in Fig.l, to actuate plunger 127 independently of the lever 1411, al-'though=movementof the'main lever arm 1355 in the same direction is alsoeffective to depress the plunger 127, since: the arm 137 is therebymoved through the agency of the abutment screw. Near its lower end arm133-is provideda slot -like opcning142 forming a driving yoke in which:a driving roller 144 actuatable by the: blower tube is fitted. Byrocking the lever 140, the stems 127;

129 may be depressed or released in the manner previously mentioned. Theaction of the lever is modified by detent means including a roller 146acting against a specially contoured upper end formed upon lever 140.The roller is urged against the upper extremity of the lever by ahelical tension spring 147 acting through a pivoted arm 149 whichcarries the roller 146.

Near the center of the upper end of the arm 139, in a position such thatthe roller when engaged therewith tends to hold the lever in a centeredposition, substantially perpendicular to and free of both of the stems127, 129, so that neither of such stems is depressed, is an angularre-entrant notch-like depression 280 positioned to be engageable by theroller 146 and so proportioned that when the roller is engaged therein,the lever is yieldably held in such centered position. To the left ofthe depression 280, as the parts are viewed in Fig. 1, the end of thelever is formed with a downwardly inclined face 282, so that when thelever is moved in a clockwise direction far enough to carry thedepression 280 to the right until the roller is forced out of the notchand the left end of the depressed portion moves to the right of thevertical radius of the roller, the roller thereafter, acting through theinclined surface 282, urges the lever clockwise to impart a snap-actionthereto and quickly depresses the stem 127. Extending to the right fromthe deepest part of the depression 280, as the parts are viewed in Fig.1, and forming the right-hand wall of the depression is an upwardlyinclined camming surface 284. The roller must roll up surface 284 whenthe lever 140 is rocked counterclockwise from the centered positionshown in Fig. 1. The reaction of the inclined portion 284 with theroller is thus such as to oppose counterclockwise movement of the leverand to return it to the centered position after the stem 129 has beendepressed.

The arm 137 is independently actuatable in a clockwise direction, todepress the stern 127, by means of an actuating plunger 285 which issecured to and actuatable by a piston 286 slidable in a cylinder 288secured to the face of the panel 123. The cylinder, piston and plunger,288, 286, 285, constitute part of an emergency reverse mechanism, theaction of which will presently be described.

The lever 140 is actuatable by means of a rod assembly 152, which is inits effect a unitary rod, although for convenience, constructed insections. The rod assembly extends longitudinally beside the casing tube77. At its forward end, the rod assembly is secured to a slide member300, slidably supported upon the back of the panel 123 for horizontalmovement in unison with the rod assembly. Slide 300 carries a pair ofstuds 154, 155, which project through and are guided in a horizontalslot 150 in the panel. Stud 155 carries roller 144, so that movement ofthe rod assembly will actuate the lever 140.

At a position corresponding to the desired limit of forward travel ofthe blower driving nut 105, and which accordingly bears a fixed relationto the degree of projection of the blower, a lug 157 rigidly securedwith respect to the rod assembly 152 projects through a slot 159 intothe interior of the casing tube 77, while at a position near the rearextremity of the casing tube and corresponding to the desired limit ofrearward travel of the actuating nut 105, a similar lug portion 160,rigidly secured with respect to the rod assembly 152 near its rear end,extends through a slot 162 into the interior of the casing tube. Thelugs 157, 160 lie in the path of movement of the actuating nut 105 andare actuated by the nut as the blower completes its forward and rearwardtravel, respectively. While the details of the mounting and actuation ofthe lugs 157, 160 may be varied widely, in the preferred constructionillustrated each such lug is housed in a casing as 170, 171, whichcovers the slot (159, 162) in the casing tube. Each such casing is openupon the side thereof which covers the slot, being tightly secured andsealed with respect to the side of the casing tube 77 in an areaentirely surrounding the slot. In each case, a lug-supporting section ofthe rod assembly 152 projects slidably through both ends of the housing,being sealed with respect to both end walls of such housing as bysealing rings 174. The forming of the rod assembly in sections promotesease of assembly and adjustment, the sections which project through thehousings 170, 171 being separably and adjustably secured to the adjacentsections, as indicated at 172, although normally rigidly secured, sothat the rod assembly functions as a unit.

8 The lugs 157, 160 and the actuating rod assembly 152 are soproportioned and positioned that as the blower completes its forwardtravel, a bearing collar 250 carried by nut strikes the lug 157, movingthe rod assembly forwardly and thereby also carrying the rear lug 160forwardly to a position forward of the rear limit of travel of the nut105. Such forward movement of the rod assembly rocks the lever in adirection to cause the arm 138 to depress the stem 127, causing the airmotor to reverse and so initiating the retracting travel of the blowertube. As the blower tube approaches the rearward limit of its travel, itstrikes the lug and in completing its rearward movement moves such lug,and resultantly the rod assembly 152, to rock the lever 140 in theopposite direction and so cause the arm 139 to depress the stern 129,and also causing an arm 434 carried by slide 300 to open a valve 406,stopping the air motor and interrupting the drive of the blower with theblower fully retracted. The action of these parts will presently beconsidered in greater detail. After the blower motor stops, the airsupply to the motor control valve assembly 121 is interrupted and thestem 127 is accordingly no longer biased by such air pressure. Stem 127is therefore again projected outwardly by the spring 130.

Where steam is used as the blowing medium, the flow of blowing steam maybe controlled by an air operated valve assembly constructed as indicatedin Fig. 17, although it will be appreciated that the details of the blowvalve are subject to variation. The blow valve assembly consists of ahollow valve body 180, having an inlet opening 184 and coupling portion182 positioned at right angles to the valve outlet pipe 93, which maycomprise the supply pipe for the blower as previously mentioned and asindicated in Figs. 2 and 4. The inlet opening comprises an enlargedchamber 184 within which is a poppet valve assembly 185 opening againststeam pressure and biased to closed position by a spring 187 mountedabove the valve body upon the valve stem 188, which extends above thebody as shown. The stem is slidable and substantially sealed withrespect to the top wall of the valve body 180, extending through a guide190 tightly secured in such top wall, the guide being externallythreaded and extending downwardly to a position close to the valve port.The valve port is defined by a hardened valve seat ring 192, to and fromengagement with the lower end of which the valve is movable when thestem 188 is actuated. The effective port area through which steam canflow when the valve is open is adjustable by means of a blocking element194, which may be of circular cross section, somewhat greater indiameter than the port in the ring 192, and mounted on the guide 190 insuch manner that it may be adjustably moved to, and fixed in, any ofvarious positions with respect to the ring 192, wherein it may block toa greater or lesser extent the flow of steam through such ring. Theblocking member 194 is internally threaded to fit upon the threads ofthe guide 190, so that by rotating such blocking member, it may be movedto and from the upper face of the ring. The periphery of the blockingmember is provided with a plurality of radial slots as 195 engageable bya locking pin 196 formed as a rigid axial extension of a plug 198 fittedin a threaded aperture 200 in the side of the valve body 180. When theplug is removed, the blocking member may be rotated by means of a drift,screw driver or other suitable instrument thrust through the opening200, and when the blocking element is thereby located in a desiredposition, with one of the slots 195 in radial alignment with the axis ofthe plug hole 200, the blocking member may be locked in position merelyby reinserting the plug 198 and simultaneously projecting the pin 196into the slot to hold the blocking member against turning on the guide.

The valve 185 is actuatable by means of a servomotor comprising acylinder 202 supported by lower and upper cylinder heads 204, 205, heldtogether by clamping bolts 206 and rigidly mounted in axial alignmentwith the stem 188 upon the upper ends of struts 189 extending upwardlyfrom casing 180. A piston 208 in the cylinder 202 has an axial rod 210extending downwardly through an opening 211 in the head 204, rod 210being engageable with the upper end of the stern 188 to open the valve185 when the piston 208 is actuated downwardly by air delivered to theupper end of the cylinder through a conduit 212. When the air pressurein the cylinder is relieved, the piston is moved upwardly by the biasingspring187.

The conduit 212 leads to a coupling 214 connected to '9 -a.,port 215formed .in one :side \of 1:he body ,portion .217 of ta :three-way valveassembly mountedon the back of panel .123. The three-way alve 217 servesto-establish and interrupta connection between the actuating cylinderv202 for the blow'valve and a source of air supply (motor .power air)under pressureas the blower tube commences its forward travel, so thatas such forward travel commences,-the blow valve element 185 is moveddownwardly off its seatandblowing steamcanflow 'intoand through thescrew-tube 79, blower tube 29, and from the nozzle 25 duringsubstantially the entire projecting and retracting movement .oftheblower tube andlnozzle. The threeway valve #217 also functions .toshut off such air supply to allow the blow valve element to reseat asvthe blower tube and nozzle complete their retracting movement. Theconstruction of the-three-way valve is subject to variation, butit isshown in Fig. 18 as comprising .a pair-of coaxial cylindricalchambers-220, 222 formed .in opposite ends of the valve body 217, suchchambers having seat portions .224, v225 at their-inner extremities, andbeing connected by a reduced axial passage 227. Valve element 229 ismounted in'the chamber 220 to move to andfrom the seat 224, and a valveelement 230 "in the chamber 222 is mounted for movement to and from theseat 225, the valve elements 229, 230 being carried by opposite ends :ofa stem 232 whichextends through .the passage227, but is materiallysmaller than such passage, so that it does not substantiallyi interferewith air flow therethrough. The double valvelassembly is biased to theright, as the parts are viewed in Fig. 1 8, by a helical compressionspring'233 arranged in the chamber 22'0'behind the valve element v2'29.The side port 15 to which the conduit 212 3 is connected communicateswith the-central passage I227. The'left end of the chamber 22%) isenlarged and tapped to receive a coupling element 234, adapted to beconnected'to aisuitable source of air under pressure or-otherappropriatemotivating fluid. Actuating plunger235 is slidable in thechamber 222 and adapted-to bear at its inner end against valve element23d, plunger 235 being provided with an extension .237 which projectsfrom the end .of the body 217. The plunger 235 is substantially smallerthan the chamber222, sothat air mayflowfreely around .the plunger andthe valve elements 229, 230 are also substantially smaller than theirrespective Chambers 220, 222.

The three-way valve .assemblyis actuated through the agency ofmechanisrncontained ina casing 219 and carried by a bracket 24!)attached to the top of the casing tube 77. A lever 24-2 is rockablysupported by a shaft .2- i3'journaled inbracket 2 50 withinthe casing219. The lever'2d2 isinthe'forni of aroc'ker arm and extends generallyparallel'to the'blower tube, vbeing'fast upon theshaft 243. A leveractuating plunger 255 is vertically 'slidable in a guide nipple 256extending through the top wall of the casing tube '77, the upper endof'the plunger 255 being formed as an enlarged head 257' engageablewithan adjustable abutment screw 2'44- carried'by one end of the lever242 forward of the'fulcrum pini2 -l3. At its lower end, the plunger'255is provided with arounded tip259 extending into the path of a bearingretaining'collarfitl carried by'the'actuating nut 165. An antrifrictionbearing assembly252 isinterposed between the nut and collar25t).

The 'collar250 slides in the casing tube 77. Aplunger 260 similar toplunger255, but spaced longitudinally therefrom,

:ha's ahead 262 engageablewith an abutmentscrew 2-2-5 carriedby lever242 .to the rear of the fulcrum pin 243, and is vertically .slidable toactuate the same. Plunger "260 is provided with a rounded lower endportion 264 which also projects into the path of the actuating nutbearingcollarZSti. The plungers 255, 266 are spaced from one another'adistance greater thanthe axial length of the collarl250,"therearmostplunger 260beinglocated a short :distance forwardly rtf theposition occupied by the traveler nutwhen thelBlOWBr is fully retracted.

.As best'shown in'Fig. '12, the'shaft 243 exten'clshorizontally to t aposition where it overhangs .oneside of the casingtube 77, suchoverhangingportion projecting laterally beyond the supporting bracket.240. A downwardly extending arm 254is fast .upon such projecting end.of'ithe shaft 243 and carriesa vertically adjustable ball jointelement.310,.the ball.portion-31 1-of which coacts with a socket.3'12which .is secured to the rear end of a forwardly extending rod315slidably supported in suitable guide brackets 3'16 .attaChed atsuitable spaced points to theside of .the casing tube 77. The-brackets10 316 may also serve to slidably support the rod assembly 152,previously mentioned. Rod 315 extends forwardly to a position justbehind the housing 17%), where it is coupled by means of a coupingmember 318 toa rod 320 which is upwardly offset a slight distance fromthe rod 315, but serves as a continuation thereof, the rods 315, 320being connected in such manner as to move as a unit. The rod 320 extendsthrough a suitable bearing guide portion 322 formed integrally with thecasing 170 and projects behind the control panel 123, where it iscoupled by means of a ball and socket connection, generally designated324, to the lower end of a lever 325 pivoted on a stud 126 mounted onthe panel and projecting from the rear face thereof. The upper end ofthe lever 325 is provided with a wedge-shaped top 32% adapted to coactwith a roller 33% carried by an arm 332 pivoted as on pin 333 upon therear face of the panel, and urged downwardly in such manner as to urgethe roller 339 against the .wedge-shaped top 328 of-the lever 325 bymeans of a helical tension spring 334-, the lower endof which is hookedupon a pin 335 carried by the panel, while the upper end of the springis secured to anadjustableabutment and coupling element 336 carried bythe arm 332. The lower end of the lever 325, upon its side opposite tothat coupled to the rod 320, is engageable with a stem 237, which formsthe actuating plunger of the three-way valve 217, previously described.The plunger 237 is surrounded by a helical compression spring 338, whichtends to rock the lever 325 clockwise, as viewed in Fig. 11, but is notstrong enough to overcome the resistance .of the spring 334.

When the blower tube is fully retracted so that the nut and collar 250lie behind the rearmost plunger 260, the plunger .260 is elevated andthe plunger 255 is depressed, as shown in Pig. 4, the rocker arm 242being tilted correspondingly, as shown in that view. The rod 329 isaccordingly drawn rearwardly, that is, to the left as viewed in Fig. 11,so that valve portion 229 (Fig. 18) is seated, the air supply throughthe conduit 212 leading to the blow valve actuating cylinder 202 is cutoff, and the blow valve actuating cylinder 202 is connected toatmospherethrough port 215, passage 227, and chamber 222. Blow valve element 185is thereby closed under the influence of the spring 187.

When the traveler nut moves forwardly during the first part of theforward travel of the blower, the collar 250 passes under plunger 260and then engages and lifts the plunger 255, throwing the lever 242clockwise, as viewed in Fig. 2, andby virtue of the overcenter meanspreviously described, thereby causing the lever 325 to snapcounterclockwise, as viewed in Fig. l1, to the other of the two extremepositions it occupies. The vent'valve element 230 is thereby closed andthe air supply valve element 229 opened, allowing air to flow to thecylinder 202 to open the main blow valve. The three-way valve is held inthis position by the overcenter means, while the blower tubemoves'throughout the remainder of the projecting and retracting portionsof the-operating cycle and until the collar 250, near the completion'ofthe retracting cycle, again engages thetip of the plunger 269 to liftthe right end of the lever 242 past the dead-center position, causingsuch lever to snap 'inthe counterclockwise direction and reassurne theposition shown in Fig. 4, whereupon therods 315, 320 function to movethe plunger 237 of the three-way valve 217 inwardly to again shut offthe air supply,'vent the actuating cylinder 202 and'allow the blow valveto close.

Although when the blower is .fully retracted the lever 149 is in'theposition shown in Fig. 19, wherein the valve stem 129 ispressedinwardly, the lever assumes the centered position shown in Fig.lupon commencement of forward travel of the blower, as the nut 105 andits bearing collar 250 move forwardly away from the lug.160 to permitthe rodassembly 1'52.to shift forwardly, so that the roller 146 maycenter thearm 140. During forward travel of the blower, motor power airenters the valve body 121 from conduit-l33ithrough port 370,.passes overthe valve element 372 carried by the stem 127through passage 388, pistonvalve chamber 374 and out of the valve body through ,port 375, =fromwhichitis delivered to the 'airmotor 4d through=conduit 376. The chamberv129. The other cylindrical chamber :is designated r378 and communicateswith the chamber of valve element 382. The cylindrical chambers 375, 378are in communication with one another through a smaller coaxial passage380, and each such cylindrical chamber contains a piston valve as 384,385. Piston valves 384, 385 move as a unit, being connected to oneanother by a common axial stem 386 which extends through the passage380. Cylindrical chamber 374 communicates with the chamber of valveelement 372 through passage 388, and chamber 378 communicates with thechamber of valve 382 through a port 390. When running forwardly toproject the blower, the air is delivered to the motor through conduit376 and exhausted therefrom through conduit 392, valve port 394, chamber378, passage 380 and port 270. It will be seen that the air enteringchamber 374 maintains the double piston valve assembly 384, 385 in theposition shown in Fig. 19, wherein the piston valves are raised and theexhaust air returning through port 394 passes under valve 385 andthrough chamber 378 and passage 380 to the exhaust port 270.

When at the completion of its forward travel, the blower shifts the rodassembly 152 forwardly to rock the lever 140 in a direction to depressthe plunger 127, the motor air is cut off from passage 388 and passesunder valve 372, through a cross-connecting passage 400 in the valvebody 121, over valve 382 and through passage 390 to cylindrical chamber378 where, acting upon the outer (upper) end of piston valve 385, itshifts such valve downwardly to seat against the upper end of axialpassage 380 and to unseat piston valve 384 from the opposite end ofaxial passage 380 and open communication between such axial passage andport 375. The air then passes from cylindrical chamber 378 through port394 to conduit 392 and is delivered by the latter conduit to a motor 40to drive the motor in the reverse direction. The motor exhaust isdelivered through conduit 376 to port 375, passes under piston valve 384and through passage 380 and port 270 to the exhaust conduit 117. Thereverse drive imparted to the blower continues until, at the completionof retracting movement of the blower, the driving nut bearing collar 250strikes the lug 160 and carries the rod assembly 152 to the rear,rocking the lever 140 counterclockwise to the position shown in Fig. 19,depressing the stem 129 and moving the valve element 382 to the positionshown, wherein it closes off communication between the connectingpassage 400 and passage 32 0. The air then passes from the connectingpassage 400 under the valve element 382 to an outlet port 402. It willbe noted that the air passing under the valve elements 372, 382maintains them in their leftward positions wherein the stems 127, 129are retracted. With both valves moved to the left, as viewed in Fig. 19,air delivery to the motor 40 is interrupted and movement of the blowerstops.

When the blower is fully retracted, the operating diaphragm chamber 410of a diaphragm valve 412 is connected through a two-way valve 406 andconduit 408 to a control line 405. Control line 405 is connected to acontrol panel (not shown) which may be arranged substantially inaccordance with the disclosure of Curtis L. Howse application Serial No.88,854, filed April 21, 1949, and now Patent No. 2,565,689. The controlconduit is adapted to deliver air at a pressure which is less than thepressure of the motor driving air delivered through conduit 133. (Forexample, the motor power air may be at a pressure of approximately 80 p.s. i., and the control air pressure may be of the order of 35p. s. i.)Valve 410 controls the delivery of air through conduit 133 to the motorcontrol valve 121. The mechanism at the control panel, which is notshown herein, but which may correspond to the disclosure of thepreviously mentioned Howse application, is so arranged that if thepressure in the control line is raised materially above the normal 35 p.s. i., the panel mechanism shuts off the control line completely andopens a relatively large vent, so that the pressure in the control linequickly drops to a value less than 35 p. s. i. This allows the diaphragmvalve 412 to close, interrupting the delivery of air to the motorcontrol valve and motor.

Valve 406 is operable by an arm 434 carried by a stem 435 forming anextension of the forward end of the slide 300. Arm 434 is rigidlysecured to stem 435, and locked in position by a lock nut 436. Stem 435is smaller than the forward end of slide 300 and a washer 433 isslidable upon the stem to and from engagement with the shoulder 437defined by the plane of juncture between the end of the slide and thestem. A helical compression spring 438 is arranged upon the stem betweenwasher 433 and arm 434 and yieldably urges the washer into engagementwith the shoulder 437. Washer 433 is also engageable with the sides of apair of abutment elements shown as the head portions of screws 439, 441,projecting from the panel 123, and which also serve as guides for theslide 300. The action of the spring 438 upon the washer 433 and the arm434 tends to draw the slide 300 and rod assembly 152 forwardly. When theblower is fully retracted, the rod assembly 152 and slide 300 are drawnto the rear, as previously explained, and the shoulder 437 is drawn awayfrom the washer 433, the spring 438 being thereby compressed, so thatthe parts stand in the position shown in Fig. 11. As soon as forwardmovement of the blower commences, and the rearward pressure upon the lug160 is relieved, the rod assembly 152 and slide 300 are permitted tomove forwardly a slight distance under the influence of the spring 438.Thus the arm 434 only moves the valve 406 to the open position when, andmaintains this valve open while, the blower is fully retracted, and onlyat such time is there communication through the valve 406 between theconduits 405, 408.

When the control panel delivers control air through the open valve 406to the diaphragm chamber 410, the valve 412 is opened to initiateforward movement of the blower, in the manner previously described.Motor power air is then delivered to the diaphragm chamber 410 through aholding connection provided by the conduit 415. Conduit 415 incorporatesa pressure reducing orifice member 416 proportioned to prevent thepressure in conduit 408 from building up to too high a value before thevalve 406 has been closed in response to forward movement of the rodassembly 152 and slide 300. Valve 406 closes very soon after the blowerstarts forward, and the pressure in the line 408 builds up toapproximately the pressure in the motor air line 133 (e. g. 80 p. s. i.)during operation of the blower.

Upon completion of the cycle of operation of the blower, the return ofthe blower tube to the fully retracted position opens the valve 406 inthe manner described, connecting the conduit 408 to the control conduit405 and thereby imposing a high pressure impulse upon the control lineto cause the mechanism at the control panel to disconnect the controlline from the 35 p. s. i. control air source and vent the control linein the manner previously mentioned. Due to the restriction at theorifice member 416, the pressure in the diaphragm chamber 410 fallsaway, due to the venting at the control panel, more rapidly than suchpressure can be maintained from the motor air source through the orificemember 416, and valve 412 accordingly closes. The pressure is therebyrelieved upon the under sides of the valves 372, 382, so that thesevalves can again be moved to the right under the influence of the valvesprings 130, 132.

During the last part of the rearward movement of the blower, the airpasses through the motor control valve casing 121 and out the outletport 402 thereof, as previously mentioned. This air is delivered throughconduit 407, check valve 430, conduit 428 and branch conduit 432 to thereversing cylinder 288, causing the stem 285 to move the arm 137 in adirection to bear inwardly against valve stem 127 and to hold the valve372 positively seated against the port 388. This positively preventsmovement of the valve 372 to the right under the influence of its spring130 during the last portion of the movement of the blower, therebyinsuring against unwanted projecting movement of the blower.

It will be noted that during operation of the blower, the system at theblower itself is entirely independent of the control panel, due to thefact that valve 406 is closed. Thus even if the control panel shouldfunction improperly so that control air pressure in conduit 405 shouldfail, the blower would continue to operate, if the operating cycle hadcommenced prior to the failure, because the motor air pressure wouldmaintain the pressure in the diaphragm chamber 410 to hold the diaphragmvalve open. This will allow the blower to complete its retractingmovement under such conditions.

The conduit 234 leading to the three-way valve 217 which controls theaction of the blow valve, in the manner previously described, isconnected to the motor air supply line 133 in advance of the diaphragmvalve 412. The

acme-1o conduit 212 from-valve 217 to the operating cylinder 202 of theblow =valve is also connected to a conduit 420 leading to a two-wayvalve '422. Valve 422 is biased to closed positionbutadapted to be heldopen by a springbiased arm 446 which overcomes the bias of the valve.While held open'bythe arm-biasing spring 448, the valve 422 providescommunication between conduit 420 and a conduit 424 which communicatesthrough a restricted pressure control assembly is connected by a conduit450 to the blowing steam "supplypipe 452 at a 'point between the blowerand the blow valve 202. So long as blowing steam is being delivered tothe blower, the pressure of the "blowing'steam, communicated to thepressure control assembly 445, overcomes the spring 443 to move the arm446 away from the valve 422, so that valve 422 remains closed. If thesupply of blowing steam should fail, however, the fall of pressure inthe unit 445 allows the spring 448 to open the valve 422. Motor powerair is thereby delivered to the emergency reverse cylinder 288 throughconduits 424, 432,and stem 235 moves valve element 372 to the left, asviewed in Fig. 19, to immediately reverse the blower, if it hadpreviously been traveling forwardly, and cause the same to be retracted.This will be recognized as a safeguard against the damage which mightresult to the blower tube if it were allowed to continue its operationwithout blowing steam. Conduit 424 contains a restriction incorporatedin an orifice member 425, serving as delaying means to prevent thefunctioning of the automatic reversing means just described for aninterval long enough to allow the blowing steam pressure to build up inthe pressure control assembly 445.

Various means may be used for supporting the rearwardly projectingportions of the blower assembly, but it will be observed that therearwardly projecting portions are of such nature that frequent accessthereto is not necessary. These parts are also such as to be virtuallyunaffected by the weather, so that they do not require enclosure within:the walls of a building, and may be carried by a skeletonized frameworkof any character which possesses the necessary mechanical strength.

The casing tube 77 is shown in Figs. 2 and 13 as supported near its rearend by a hanger structure, including a supporting clamp having asemicircular body portion 350 to which holding lug portions 352, 354 arebolted, the lug "portions 352, 354 being proportioned to par.-

tially embrace the casing tube, but to clear the rod structure and rearhousing 171. The body portion 350 may be supported by a rod 355 attachedto the upper end thereof by a clevis 356, and it will be appreciatedthat another clevis as 358 may be secured to the lower end of the bodyand that subjacent blower assemblies may be hung therefrom. The rear endof the casing assembly 27 is also supported by a hanger rod 360 securedto a flange 362 formed upon the rear end of said casing. A manuallyoperable valve as 527 may be provided between lines 234, whichcommunicates with motor power air line 133, and line 408 connected todiaphragm chamber v 410 of valve 412. Valve 527 is of course normallyclosed,

but may be opened for manual operation or test.

In Figs. and 21, I have shown a somewhat modified driving arrangementwherein the friction driving rollers are eliminated and the blower tube,designated 20a, is of polygonal cross section and slidably fitted in aninternal opening of similar cross section in the sleeve a, whichcorresponds in its general arrangement to the sleeve 35 of the firstembodiment. The sleeve 35a may be driven in an analogous manner by aworm 39a and wormwheel 37a, and due to the keying effect of theinterfitted portions of polygonal cross section, the driving rollers andassociated parts may be entirely eliminated. Preferably the externalportions of the sleeve 35aare of circular cross section, as indicated inFig. 21., to facilitate the rotatable support thereof in the supportingbearings 32a, 33a, and to enable the use of conventional llubricant'retaining sealing rings as 36a, 42a.

. Pi'g. 22 shows a modification wherein the blower tube 20b is ofcircular cross section'as =in'th'e'first embodiment, but is provided inits external wall with a straight longitudinal keyway 500, whichslidably overengages a key 502 carried by and projecting inwardly fromthe inner wall of the sleeve 35b. The keyserves as driving means so thatin this embodiment also the driving rollers may be eliminated and thedriving components may 'be arranged substantially as indicated in Fig.20.

in the further modification illustrated in Fig. 23, the rotary drivingmeans may be of any of the forms previously mentioned, although forpurposes of illustration it may be assumed that the rotary driving meanscorresponds to that disclosed in connection with the first describedembodiment. The-central fee'd tube'79'c, which may be positioned andsupported similarly to the screw tube 79 of the first embodiment, is notprovided with threads. Packing, generally designated 820, is carried bythe outer end of the tube 790 and the blower tube 200 is slidably fittedover such packing. Secured to the rear end of the blower tube is apacking assembly 5% which extends inwardly into sealed engagement withthe smooth outer surface of the feed tube 7%. The space sac between thetubes 20c, 79c is thereby sealed. The blower tube also carries anoutwardly projecting sealing piston portion 598 which projects intosubstantially sealed, but slidable, engagement with the inner wall ofthe casing tube 770.

in order to project the blower tube, a suitable motivating fluid, whichmay comprise air under pressure, is forced into the space behind thepiston 598, between such piston and the back wall c, which closes at therear end the annular space between the feed tube 7 9c and easing tube770. Fluid for projecting the blower in this manner may be suppliedthrough a conduit 376a from a suitable source (not shown) to a fitting512 extending through the casing tube 770 near the rear end of thelatter. During projection of the blower, the space 506 is vented througha conduit 514 which extends longitudinally through the feed tube 790,being connected at its forward end to a fitting 515 which providescommunication between the conduit and the forward end of the space 5%directly behind the packing 820. At its rear end, the conduit 514extends outwardly through the back wall portion 990 and communicateswith a fitting 51.6 to which a conduit 3920 is connected. Fluid pressureis vented from the space 5% during projection of the blower through theconduit 3920, while in order to retract the blower, fluid under pressureis supplied through the conduits 392e, 5114 to the space 506 and thespace to the rear of the piston 503 is vented through the conduit 3760.

It will be recognized that the control of this embodiment may also beanalogous to the control means employed in the first embodiment. The airor other fluid for projecting the blower into the boiler suppliedthrough conduit 3760 may be analogous to the air supplied to the airmotor in the first embodiment through the conduit 376, while the conduit392s of this embodiment corresponds to the conduit 392 of thefirstembodiment, serving to conduct exhaust fluid away from the blowerduring projecting movement and to conduct fluid to the blower duringretracting movement. The other principal components of the blower mayalso correspond to those of the previously described embodiments, anddetailed reconsideration will not be required.

While it will be apparent that the preferred embodiments of theinvention herein disclosed are Well calculated to fulfill the objectsabove stated, it will be appreciated that the invention is susceptibleto modification, variation and change without departing from the properscope or fair meaning of the subjoined claims.

What is claimed is:

l. A slidably extensible and retractable soot blower constructioncomprising guiding and supporting means including a stationaryexternally threaded guide tube having a free end portion adapted toextend forwardly toward a zone wherein a cleaning function is to beperformed, means for securing the guide tube at a point spacedrearwardly of such zone and for feeding cleaning fluid to the interiorof such guide tube, the guide tube having an opening in the region ofits forward extremity, a blower tube rotatably and slidably surroundingthe guide tube, an actuating nut secured to a rear portion of the blowertube and threadedly interengaged with the threads of the guide tube, andmeans located in a position forwardly of the rear extremity of the guidetube and engaged with a surface portion of the blower tube for rotatingthe same to thereby turn the actuating nut and resultantly drive theblower tube longitudinally with respect to the guide tube.

2. A blower assembly as defined in claim 1 wherein said actuating meansfor rotating the blower tube comprises a wedging roller element mountedfor concentric rotation about an axis generally parallel to a tangent tothe blower tube and also bodily rotatable in an orbit concentric withthe blower tube.

3. A blower assembly as defined in claim 1 wherein said actuating meansfor rotating the blower tube comprises a wedging roller element mountedfor concentric rotation about an axis generally parallel to a tangent tothe blower tube and also bodily rotatable in an orbit concentric withthe blower tube and frictionally engageable with the surface of theblower tube to turn the latter about the axis of the blower tube, saidroller element being rotatable about the first-mentioned axis inresponse to longitudinal movement of the blower tube.

A soot blower assembly as defined in claim 1 wherein said means forrotating the blower tube about its axis comprises a wedging rollerbodily rotatable in an orbit substantially concentric with the axis ofthe blower tube, the geometric axis of the roller lying in a planetransverse to such axis of the blower tube, and the carrier forsupporting and driving said roller in its planetary movement includingan element supporting said roller for limited rocking movement about anaxis extending transversely through the roller and substantiallyparallel to the blower tube axis.

5. A soot blower assembly as defined in claim 1 wherein said means forrotating the blower tube about its axis comprises a wedging rollerbodily rotatable in an orbit substantially concentric with the axis ofthe blower tube, the geometric axis of the roller lying in a planetransverse to such axis of the blower tube, and the carrier forsupporting and driving said roller in its planetary movement includingan element supporting said roller for limited rocking movement about anaxis substantially parallel to the blower tube axis, said roller beingof gradually increasing diameter from an intermediate portion toward anend thereof, the axis of rocking movement extending transversely througha portion of said roller of reduced diameter, and said roller beingnon-concentric with the blower tube in all projections of the roller.

6. A soot blower assembly as defined in claim 1 wherein said means forrotating the blower tube about its axis comprises a wedging rollerbodily rotatable in an orbit substantially concentric with the axis ofthe blower tube, the geometric axis of the roller lying in a planetransverse to such axis of the blower tube, and the carrier forsupporting and driving said roller in its planetary movement includingan element supporting said roller for limited rocking movement about anaxis substantially parallel to but outspaced from the blower tube axis,said roller being of gradually increasing diameter from an intermediateportion toward an end thereof, the axis of rocking movement extendingtransversely through a portion of said roller of reduced diameter, andmeans drivingly connecting the carrier to the roller including a gimbalelement rockable in the carrier upon said axis parallel to but outspacedfrom the axis of the blower tube and defining a gimbal axis, such gimbalaxis being spaced farther from the blower tube than is the geometricaxis of the roller.

7. A soot blower assembly as defined in claim 1 wherein said means forrotating the blower tube about its axis comprises a wedging rollerbodily rotatable in an orbit substantially concentric with the axis ofthe blower tube, the geometric axis of the roller lying in a planetransverse to such axis of the blower tube, and the carrier forsupporting and driving said roller in its planetary movement includingan element supporting said roller for limited rocking movement about anaxis substantially parallel to but outspaced from the blower tube axis,said roller being of gradually increasing diameter from an intermediateportion toward an end thereof, the axis of rocking movement extendingtransversely through a portion of said roller of reduced diameter, meansdrivingly connecting the carrier to the roller including a gimbalelement rockable in the carrier upon said axis parallel to but outspacedfrom the axis of the 16 blower tube and defining a gimbal axis, suchgimbal axis being spaced farther from the blower tube than is thegeometric axis of the roller, and means biasing said gimbal element androller in one angular direction about said gimbal axis.

8. A slidably extensible and retractable soot blower constructioncomprising guiding and supporting means including a stationary guidetube having a free end portion adapted to extend forwardly toward a zonewherein a cleaning function is to be performed, means for securing theguide tube at a point spaced rearwardly of such zone and for feedingcleaning fluid to the interior of such guide tube, the guide tube havingan opening in the region of its forward extremity, a blower tuberotatably and slidably surrounding the guide tube, drive mechanismlocated in a position forwardly of the rear extremity of the guide tubeand engageable with a surface portion of the blower tube for rotatingthe latter, means completely enclosing the portion of the soot blowerconstruction lying outside said zone, including a stationary casing tubesurrounding said blower tube, a housing portion enclosing said drivemechanism and communicating interiorly with said casing tube, and afluid motor for driving said means for rotating the blower tube, saidmotor having an exhaust portion connected to said casing tube at aposition rearwardly of the housing portion, whereby the exhaust of themotor is conducted through the casing tube and housing portion, andmeans for projecting and retracting the blower tube through the casingtube and housing portion.

9. Means for rotating a rotatable and longitudinally movable tube,including a carrier rotatable externally of and substantiallyconcentrically with the tube, and a friction driving roller carried bythe carrier and engageable with the tube to exert tangential forcethereon to turn the same, said roller being rotatable in the carrier onan axis transverse to the tube whereby it may rotate about suchtransverse axis during longitudinal movement of the tube and beingrockable about an axis substantially parallel to but spaced outwardlyfrom the tube, the tube-engaging surface of the roller diverging fromthe surface of the tube in a direction parallel to the axis of theroller and away from the center of the roller, whereby such rockingpermits the roller to move to and from tight wedging relation with thetube.

10. Means for rotating a rotatable and longitudinally movable tube,including a carrier rotatable externally of and substantiallyconcentrically with the tube, and a friction driving roller carried bythe carrier and engageable with the tube to exert tangential forcethereon to turn the same, said roller being rotatable in the carrier onan axis transverse to the tube whereby it may rotate about suchtransverse axis during longitudinal movement of the tube and beingrockable about an axis substantially parallel to but spaced outwardlyfrom the tube, said last-mentioned axis being spaced outwardly from thetube farther than the transverse axis, the tubeengaging surface of theroller diverging from the surface of the tube in a direction parallel tothe axis of the roller and away from the center of the roller, wherebysuch rocking permits the roller to move to and from tight wedgingrelation with the tube.

11. Means for rotating a rotatable and longitudinally movable tube,including a carrier rotatable externally of and concentrically with thetube, a pair of friction driving rollers mounted in the carrier, saidrollers having surface portions tangent to the tube in two angularlydisposed planes and being rotatable in the carrier on transverse axesand also limitedly shiftable in transevrse planes to and from tightwedging relation with the tube.

12. Means for rotating a rotatable and longitudinally movable tube,including a carrier rotatable externally of and concentrically with thetube, a pair of friction driving rollers mounted in the carrier, saidrollers having surface portions tangent to the tube in two angularlydisposed planes and being rotatable in the carrier on transverse axesand also limitedly shiftable in transverse planes to and from tightwedging relation with the tube, means biasing said rollers in oppositeangular directions in said transverse planes of shifting movement, and areaction roller engaging a surface portion of the tube in opposedrelation to the driving rollers.

13. A slidably extensible and retractable soot blower constructioncomprising a stationary guide tube, a blower tube slidably and rotatablycarried by the guide tube, a

stationary casing tube open at its front end and proportioned to permitthe blower tube to project into and from such front end, said casingtube surrounding the rearwardly extending portion of the blower tube andbeing substantially sealed with respect to the guide tube at a point tothe rear of the blower tube, the forward end of the guide tube openinginto the interior of the blower tube, and means appurtenant to theforward portion of the casing tube and including a rotatable collarsurrounding and operatively connected to the blower tube for rotatingthe blower tube, said blower tube and collar having nonconcentricinterfitted driving portions and the interior of the blower tube beingof substantially circular cross section.

14. A slidably extensible and retractable soot blower constructioncomprising a stationary guide tube, a blower tube slidably and rotatablycarried by the guide tube, a stationary casing tube open at its frontend and proportioned to permit the blower tube to project into and fromsuch front end, said casing tube surrounding the rearwardly extendingportion of the blower tube and being substantially sealed with respectto the guide tube at a point to the rear of the blower tube, the forwardend of the guide tube opening into the interior of the blower tube,means for projecting and retracting the blower tube comprising a drivingelement rotatable in one direction to project the blower tube and in areverse direction to retract the blower tube and projecting inwardlyacross a front end portion of the casing tube into engagement with theblower tube, and means for reversing the direction of rotation of saidelement including a pair of shiftable trip members carried by saidcasing tube at longitudinally spaced positions therealong and projectinginwardly through the casing tube into engageable relation with respectto a coacting abutment carried by the blower tube, and reversible motormeans having a driving connection with said driving element andoperatively connected to said trip members.

15. An extensible and retractable soot blower assembly comprising astationary tubular guide member, means for supporting the guide memberfrom one end thereof with the other end of such guide member projectingforwardly toward a Zone to be cleaned, a blower tube slidably mountedupon said guide member, driving means including a driving partsurrounding the blower tube at a point spaced forwardly from thesupported end of the guide member and engageable with the blower tube toinduce longitudinal movement thereof, an elongated casing and supportingstructure extending rearwardly from a position near the forward end ofthe blower tube when the blower tube is retracted to a position near therear of said guide element, said casing and supporting structuresurrounding said blower tube, a part of said structure near said forwardposition and which constitutes less than the full supporting structurebeing displaceable, and sealing means interconnecting the forward end ofsaid guide member and the interior of the blower tube and accessiblethrough the opening formed by displacement of the displaceable part ofsuch structure.

16. An extensible and retractable soot blower assembly comprising astationary tubular guide member, means for supporting the guide memberfrom one end thereof with the other end of such guide member projectingforwardly toward a zone to be cleaned, a blower tube slidably mountedupon said guide member, means for causing longitudinal travel of theblower tube including driving means surrounding the blower tube at apoint spaced forwardly from the supported end of the guide member andengageable with the blower tube to drive the same, and sealing meanscarried by the forward end of said guide member and slidably engagingthe interior of the blower tube.

17. An extensible and retractable soot blower assembly comprising astationary tubular guide member, means for supporting the guide memberfrom one end thereof with the other end of such guide member projectingforwardly toward a zone to be cleaned, a blower tube slidably mountedupon said guide member, means for causing longitudinal travel of theblower tube including driving means surrounding the blower tube at apoint spaced forwardly from the supported end of the guide member andengageable with the blower tube to drive the same, and sealing meanssubstantially fixed with relation to the guide member and slidablyinterconuecting the forward end of said guide member and the interior ofthe blower tube, the blower tube being shorter than the guide member.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 642,885 Swasey Feb. 6, 1900 702,509 Titus June 17, 1902711,851 Hanson Oct. 21, 1902 793,834 Hodge July 4, 1905 1,114,231Chapman Oct. 20, 1914 1,680,125 Bowers Aug. 7, 1928 2,104,003 SchieiferDec. 28, 1937 2,126,683 Howse et al. Aug. 9, 1938 2,187,405 SmethersJan. 16, 1940 2,200,663 Wilson May 14, 1940 2,201,733 Kollmann May 21,1940 2,202,446 Esseling May 28, 1940 2,249,741 Bowers et al. July 22,1941 2,309,889 Eves Feb. 2, 1943 2,316,117 Tilley Apr. 6, 1943 2,441,112Hibner et al. May 4, 1948 2,486,585 Brelsford Nov. 1, 1949 2,491,838Thomas Dec. 20, 1949 2,493,656 Clench Jan. 3, 1950

